WASHINGTON (CNN) -- A special court ruled Thursday that evidence presented in three cases by parents of children with autism did not prove a link between autism and certain early childhood vaccines.

A special court denied Mike and Theresa Cedillo's claim that vaccines caused autism in their daughter, Michelle.

The ruling came from a panel of "special masters" who began hearing three test cases in 2007 involving children with autism -- a disorder that their parents contend was triggered by the vaccine against measles, mumps and rubella combined with vaccines containing thimerosal, a preservative containing mercury.

Three families -- the Cedillos, the Hazelhursts and the Snyders -- sought compensation from the Vaccine Injury Compensation Program, but the panel ruled that they had not presented sufficient evidence to prove that the childhood vaccines caused autism in their children.

"I feel deep sympathy and admiration for the Cedillo family," Special Master George L. Hastings Jr. wrote in his ruling in the case involving 14-year-old Michelle Cedillo, who cannot speak, wears a diaper and requires round-the-clock monitoring in case she has a seizure.

"And I have no doubt that the families of countless other autistic children, families that cope every day with the tremendous challenges of caring for autistic children, are similarly deserving of sympathy and admiration. However, I must decide this case not on sentiment, but by analyzing the evidence," Hastings wrote. "In this case the evidence advanced by the petitioners has fallen far short of demonstrating such a link." Dr. Gupta: A look at the life of Michelle Cedillo »

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In a statement shortly after the release of the decisions, the U.S. Department of Health and Human Services said it continues to support research "to better understand the cause of autistic disorders and develop more effective methods of treatment."

However, "the medical and scientific communities ... have found no association between vaccines and autism."

"Hopefully, the determination by the Special Masters will help reassure parents that vaccines do not cause autism," the statement said.

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A litigation steering committee is representing thousands of families that fall into three categories: those that claim that the measles, mumps and rubella vaccine can combine with thimerosal-containing vaccines to cause autism; those who claim thimerosal-containing vaccines alone can cause autism; and those who claim that MMR vaccines, without any link to thimerosal, can cause autism.

Prior to the release of Thursday's rulings, an attorney for the families, Thomas Powers, said the expected rulings would affect only the families that fall under the first category.